Number of Twopins positions.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =7a(5) =11a(6) =16a(7) =26a(8) =40a(9) =65a(10) =101a(11) =163a(12) =257a(13) =416a(14) =663a(15) =1073a(16) =1719a(17) =2781a(18) =4472a(19) =7236a(20) =11664a(21) =18873a(22) =30465a(23) =49293a(24) =79641a(25) =128862a(26) =208315a(27) =337061a(28) =545071a(29) =881943